Eudoxus (and Plato)

After Socrates’ death, his most devoted follower, Plato, founded his famous institution of higher learning, the Academy, inspired in part by the Pythagoreans. Upon challenging his colleagues to explain the motions of the planets in terms of perfect uniform circular motion, his former student Eudoxus invented the first geometric model of planetary motion. Soon after, another member of the Academy, Heracleides, proposed that the earth rotates on an axis once a day.